It is known to process a search index, of an online search service, to determine a level of popularity of query terms made in a given time period, such as during a given day. Conventionally, such popularity determinations are made based on transaction data in a data warehouse, and it can take up to two to three days for the search query data in the data warehouse to be processed and the search index (with information about the popularity level of query terms) to be built and cleansed. Furthermore, the resolution of the popularity determinations (for example, temporally and geographically) may be limited.